But, even as basic math skills have evened out in many countries, differences in spatial reasoning abilities have not followed as quickly, even in places like Sweden and Norway, where math skills are now equal. This raises the prospect that there is some biological difference between the sexes—it just isn't basic math. A new study in PNAS, however, suggests that spatial reasoning differences may also be the product of society.

The study takes advantage of a convenient natural experiment. There are two tribes in Northeast India that are very similar in many ways. They both share the same agrarian lifestyle and diet, reside in close proximity, and DNA tests indicate that they are closely related. The biggest difference between them is culture. Among other differences, the Karbi are patrilineal; women do not typically own land, and the oldest son inherits the family's property after the death of the parents. The Khasi could not be more different in this regard. Men are not allowed to own land at all, any money or goods earned by a male are handed over to his wife or sister, and inheritances go to the youngest daughter in the family.

The authors of the new paper have gone to the areas occupied by the different tribes, and surveyed occupants from four villages in each. They were given the task of solving a simple three-dimensional puzzle that involved four blocks, with portions of a picture on a single face. The subjects would have to identify the correct side of the block, rotate it to the top, and then arrange the pieces to re-form the picture. To provide a bit of incentive, the authors would give anyone who could solve it in under 30 seconds the rough equivalent of a quarter of a day's wages in the area. All told, nearly 1,300 villagers agreed to participate.

In the patrilinial society, men outperformed women on this task, taking 35 percent less time to complete it than the females. That difference vanishes when the test is given to the matrilinial tribe members; there was simply no significant difference between the sexes.

The authors looked at some of the cultural factors that might be expected to explain the difference between the two societies. Males are likely to receive more education in the patrilineal society, and the authors found that introducing education as a factor in their analysis accounted for a third of the difference. Male ownership of the home also had a large effect; the gender gap is only a third the size in homes that are not owned solely by males.

Other factors don't seem to have a significant impact. Those who would be inheriting the property, either male or female, didn't outperform their siblings of the same sex. A separate test of competitiveness did not seem to have any correlation with the performance in the puzzle solving test.

In their conclusions, the authors are careful to state that the work demonstrates that culture influences spatial performance "in the task that we study." That task definitely requires spatial reasoning, but it certainly doesn't tax the full suite of abilities that humans can master. They also note that their work is correlative, and its implications "should be taken with a grain of salt, because causality cannot be ascertained." I'd add that the abilities of the tribes in Northeast India are only ever going to provide a small snapshot of the full range of human diversity.

What the study does do is narrow the range of things that we can readily describe to innate abilities. It also provides a clear indication that at least some spatial skills appear to be significantly influenced by cultural factors. There may yet be places where innate differences in math and spatial reasoning exist between the sexes, but those places are becoming ever smaller.

199 Reader Comments

In the patrilinial society, men outperformed women on this task, taking 35 percent less time to complete it than the females. That difference vanishes when the test is given to the matrilinial tribe members; there was simply no significant difference between the sexes.

Does this quotation mean that in the matrilinial tribe, both sexes did as well or in the combination of both tribes, both sexes did as well? The former would be at odds with the conclusion of the study.

It seems that the study actually verifies that there is an innate difference in spatial abilities between men and women. I mean, if the results in both sexes solving the puzzles are pretty much even in the matrilinial society, then simple logic dictates that in a society where all is truly equal, men would maintain an edge in spatial abilities. I should probably read the study itself.

Well the incentive seems that it would skew things considerably. If the men in that second group don't get to keep the money anyway, it's not much of an incentive to them. So the study might show that a quarter of a day's wages is enough to get women to step up to the men's baseline (no incentive) level.

Well the incentive seems that it would skew things considerably. If the men in that second group don't get to keep the money anyway, it's not much of an incentive to them. So the study might show that a quarter of a day's wages is enough to get women to step up to the men's baseline (no incentive) level.

Well the incentive seems that it would skew things considerably. If the men in that second group don't get to keep the money anyway, it's not much of an incentive to them. So the study might show that a quarter of a day's wages is enough to get women to step up to the men's baseline (no incentive) level.

I disagree. Even if you're not the one spending it, bringing home a tidy sum for the family is almost always liable to make you look good.

It seems that the study actually verifies that there is an innate difference in spatial abilities between men and women. I mean, if the results in both sexes solving the puzzles are pretty much even in the matrilinial society, then simple logic dictates that in a society where all is truly equal, men would maintain an edge in spatial abilities. I should probably read the study itself.

I think the key point is "in a society where all is truly equal". The authors do not seem to imply that. There may be many other factors at play to give the men an advantage and perhaps their matriarchal society (as it pertains to property inheritance) just evens the playing field. Definitely merits further investigation.

I agree with those saying this study might actually support a biological difference in spatial reasoning between the sexes. In the male-dominated society, males did better on the test. In the female-dominated society, females did NOT do better than the males. They simply pulled even.

Attempts to reduce all male/female differences to mere cultural and social factors aren't likely to succeed. There are major anatomical differences between male and female brains. The region that unites the two hemispheres, for instance, is much larger in women. That's probably the reason for women's intuition. They're better at combining what their eyes see in body language with what their ears detect in intonation. And it fits with our social history. Being physically weaker, women have more need to pick up danger signals in behavior.

In addition, studies of brain activity have shown that men and women use different parts of their brains to process mathematical and spacial problems than men. That too has a reason. For much of humanity's existence men have needed spacial skills more (for hunting and fighting) than have women (child care and harvesting). The result is imbedded in our brains.

One of the real reasons for the narrowing the performance gap between men and women probably lies in our school system, at least up to the post-graduate level. At the primary and secondary level, schools have become a male-hostile environment staffed mostly by women. Typically female behaviors (i.e. cooperation) are rewarded, while male behaviors (i.e. aggressiveness) are punished. In these schools, girls can be girls but boys can't be boys. The resulting male-hostile climate leaves boys uncomfortable and less interested in education. You see the result in the attendance and graduation rates of colleges.

You can even see that male hostility in college advertising. Semester after semester, the course catalog released by a community college near me has photos that feature women some 80% of the time. In fact, in the latest issue, virtually the only pictures with men were in situations like a dance class where they had to show male/female partners. And the online University of Phoenix ads on cable channels probably feature three women for every man. The hidden message: College is for women, grunt work is for men.

That hostility to maleness is also probably one major factor in declining incomes among the middle-class. Women are now more likely to get a college degree than men but they then set aside that income-making potential to become mothers. Their husbands, who perhaps never went to college or dropped out without degree, may be quite willing to work long hours to support their families. But without the proper credentials, they can't earn as much money.

And yes, I think men-hating feminists have a lot to do with this. Many of them simply don't like men as men.

The notion that both sexes are equal seems utterly ridiculous to me. There are huge differences in the way each sex reasons and behaves, not to mention the physical differences between the two. Such differences would logically give each sex strengths and weaknesses compared to the opposite sex.

"What the study does do is narrow the range of things that we can readily describe to innate abilities."

How does this study prove anything beyond the specific numbers that were measured for some specific test of a few specific people? There is absolutely no conceptual basis for making any kind of generalization at all.

I'm glad that I am not the only one who thought this. Not saying it is true, just that it is equally plausible.

It's not, though: how would such a consistent difference in female spatial reasoning, across two otherwise nearly identical societies, arise?

It's not genetic; the two societies are very closely related genetically.It's not geographic; they both live in the same area.It's not education; after controlling for educational level there was still a significant difference.

If it ain't nature, it pretty much has to be nurture, i.e. societal. The only major difference between the two tribes appear to be the expectations placed on, and amount of power given to, the women.

The study presents reasonably strong evidence that the spatial ability gap correlates with social roles. However, the study doesn't provide particularly strong evidence, one way or another, about whether there's an additional gender-inherent component.

In particular, it's a mistake to assume that the females in the matriarchal society would necessarily show a corresponding advantage. These two societies are not going to be exact mirrors of each other. It seems totally possibly that the males in a female-dominant society, especially an agricultural one, would retain more social power. At the minimum, physical size and strength seem to set a limit to the degree a female could "dominate" the male in this society.

Maybe spatial ability is in some way inherently stronger in males. Maybe it is a social artifact. The study certainly doesn't prove equality in this ability. But neither does the lack of female advantage in the second tribe imply an inherent difference.

I agree with those saying this study might actually support a biological difference in spatial reasoning between the sexes. In the male-dominated society, males did better on the test. In the female-dominated society, females did NOT do better than the males. They simply pulled even.

It also may show a societal influence as well. Both may be factors.

No, the article clearly said the gap between the matriarchal women and the patriarchal men vanished. It said nothing about the gap between men and women in the matriarchal society.

Riddle me this. How can one approach this ethical statement from a strictly scientific/humanist viewpoint with a straight face? Start applying scarcity, and it'll all shake out really quickly.

I mean, I believe the statement -- but my reasons for it are independent of the fact that I live in a food/shelter/water-saturated society. Any insights would be appreciated -- this is not an attempt to troll.

"Because that was how I was taught" can't be accepted, because I tend to think generationally. It won't pass on reliably. "Because I developed my own moral/ethical framework myself" is not reasonable, because we don't live in a social/ethical vacuum at all.

What's the motive to ignore abilities as a measure intrinsic value from a rational point of view?

Attempts to reduce all male/female differences to mere cultural and social factors aren't likely to succeed. There are major anatomical differences between male and female brains. The region that unites the two hemispheres, for instance, is much larger in women. That's probably the reason for women's intuition. They're better at combining what their eyes see in body language with what their ears detect in intonation. And it fits with our social history. Being physically weaker, women have more need to pick up danger signals in behavior.

In addition, studies of brain activity have shown that men and women use different parts of their brains to process mathematical and spacial problems than men. That too has a reason. For much of humanity's existence men have needed spacial skills more (for hunting and fighting) than have women (child care and harvesting). The result is imbedded in our brains.

One of the real reasons for the narrowing the performance gap between men and women probably lies in our school system, at least up to the post-graduate level. At the primary and secondary level, schools have become a male-hostile environment staffed mostly by women. Typically female behaviors (i.e. cooperation) are rewarded, while male behaviors (i.e. aggressiveness) are punished. In these schools, girls can be girls but boys can't be boys. The resulting male-hostile climate leaves boys uncomfortable and less interested in education. You see the result in the attendance and graduation rates of colleges.

You can even see that male hostility in college advertising. Semester after semester, the course catalog released by a community college near me has photos that feature women some 80% of the time. In fact, in the latest issue, virtually the only pictures with men were in situations like a dance class where they had to show male/female partners. And the online University of Phoenix ads on cable channels probably feature three women for every man. The hidden message: College is for women, grunt work is for men.

That hostility to maleness is also probably one major factor in declining incomes among the middle-class. Women are now more likely to get a college degree than men but they then set aside that income-making potential to become mothers. Their husbands, who perhaps never went to college or dropped out without degree, may be quite willing to work long hours to support their families. But without the proper credentials, they can't earn as much money.

And yes, I think men-hating feminists have a lot to do with this. Many of them simply don't like men as men.

Shouldn't the women in the matrilineal society have performed 35% faster than the men in order to show there was no innate gap?

Isn't that implied when they say the gap between matriarchal women and patriarchal men was 0?

"In the patrilinial society, men outperformed women on this task, taking 35 percent less time to complete it than the females. That difference vanishes when the test is given to the matrilinial tribe members; there was simply no significant difference between the sexes."If women didn't perform better in the matrilinial tribe it suggests an innate gap. But like 5 people beat me to that argument.

I'd be rather surprised if these two assumptions (which many people here seem to make) are true:

1) The X and Y chromosomes code for a significant amount of brain structure2) Those structural differences correlate significantly to testable psychological abilities

There's actually a small fraction of infants born with the XY chromosome pair, but due to androgen insensitivity and other factors end up with a female phenotype and get raised as girls. They're a varied group (some have testes in place of ovaries; most but not all are unable to bear children; many are indistinguishable from XX-type girls except with careful genetic screening; etc) but they might provide some additional insight to these sort of hypotheses.

Riddle me this. How can one approach this ethical statement from a strictly scientific/humanist viewpoint with a straight face? Start applying scarcity, and it'll all shake out really quickly.

I mean, I believe the statement -- but my reasons for it are independent of the fact that I live in a food/shelter/water-saturated society. Any insights would be appreciated -- this is not an attempt to troll.

"Because that was how I was taught" can't be accepted, because I tend to think generationally. It won't pass on reliably. "Because I developed my own moral/ethical framework myself" is not reasonable, because we don't live in a social/ethical vacuum at all.

What's the motive to ignore abilities as a measure intrinsic value from a rational point of view?

Values can't really be rationalized. You might use logic inside of a value system (e.g. two good things are better than one, or one good thing plus one bad thing is worse than just one good thing), but the value judgments at the "bottom" or foundation of the system are arbitrary. Deciding that each human is of equal value has to be a primary, fundamental, arbitrary choice. You can't reason yourself to that conclusion.

I agree with those saying this study might actually support a biological difference in spatial reasoning between the sexes. In the male-dominated society, males did better on the test. In the female-dominated society, females did NOT do better than the males. They simply pulled even.

It also may show a societal influence as well. Both may be factors.

No, the article clearly said the gap between the matriarchal women and the patriarchal men vanished. It said nothing about the gap between men and women in the matriarchal society.

OC, I am pretty sure you are misreading the article.

"That difference vanishes when the test is given to the matrilinial tribe members; there was simply no significant difference between the sexes."

In the patrilinial society, men outperformed women on this task, taking 35 percent less time to complete it than the females. That difference vanishes when the test is given to the matrilinial tribe members; there was simply no significant difference between the sexes.

So we have the 35% gap between men and women in the patrilinial society.We have that gap disappear when measuring women in the matrilinial society.

That can be read as either women and men performing equally in the matrilinial society, or that women outperformed men in the matrilinial society but equal to the men in the patrilinial society. The issue is the term "that", which doesn't indicate which to populations was being measured.

sigh... One of the first things I learned about feminism is that EVERYONE talks past each other. Inkling, I think you might have made a good point or two, but you're using a lot of jargon and overgeneralization. I can't even tell if your post is off-topic. Try using normal English and give specific examples.

Attempts to reduce all male/female differences to mere cultural and social factors aren't likely to succeed. There are major anatomical differences between male and female brains. The region that unites the two hemispheres, for instance, is much larger in women. That's probably the reason for women's intuition. They're better at combining what their eyes see in body language with what their ears detect in intonation. And it fits with our social history. Being physically weaker, women have more need to pick up danger signals in behavior.

In addition, studies of brain activity have shown that men and women use different parts of their brains to process mathematical and spacial problems than men. That too has a reason. For much of humanity's existence men have needed spacial skills more (for hunting and fighting) than have women (child care and harvesting). The result is imbedded in our brains.

One of the real reasons for the narrowing the performance gap between men and women probably lies in our school system, at least up to the post-graduate level. At the primary and secondary level, schools have become a male-hostile environment staffed mostly by women. Typically female behaviors (i.e. cooperation) are rewarded, while male behaviors (i.e. aggressiveness) are punished. In these schools, girls can be girls but boys can't be boys. The resulting male-hostile climate leaves boys uncomfortable and less interested in education. You see the result in the attendance and graduation rates of colleges.

You can even see that male hostility in college advertising. Semester after semester, the course catalog released by a community college near me has photos that feature women some 80% of the time. In fact, in the latest issue, virtually the only pictures with men were in situations like a dance class where they had to show male/female partners. And the online University of Phoenix ads on cable channels probably feature three women for every man. The hidden message: College is for women, grunt work is for men.

That hostility to maleness is also probably one major factor in declining incomes among the middle-class. Women are now more likely to get a college degree than men but they then set aside that income-making potential to become mothers. Their husbands, who perhaps never went to college or dropped out without degree, may be quite willing to work long hours to support their families. But without the proper credentials, they can't earn as much money.

And yes, I think men-hating feminists have a lot to do with this. Many of them simply don't like men as men.

This is a litany of post hoc fallacies.

Have you every looked up what he is describing? There is research validating what he is saying.

I'll just leave you with one little thing... Have you ever noticed any commercials where a man is confused, but a woman comes to the rescue or gives him the advice, making her seem smart and educated while he is portrayed as dumb? There never seem to be any commercials to the opposite.

It seems that the study actually verifies that there is an innate difference in spatial abilities between men and women. I mean, if the results in both sexes solving the puzzles are pretty much even in the matrilinial society, then simple logic dictates that in a society where all is truly equal, men would maintain an edge in spatial abilities.

That may seem like a reasonable inference, but it's not a logical conclusion. Cultures are far too complex to assume that we can somehow "average" the matrilineal and patrilineal cultures, then average performance on this test and conclude that men have innately superior spatial abilities. There may be other reasons that women in the matrilineal society do not outperform men on spatial reasoning. There are far too many variables to say that men have an innate edge.

The study shows, at most, that it is possible to achieve gender equality in spatial reasoning.

I think one of the confusing points right now is whether the performance gap between matriarchal males and females, or between matriarchal females and patriarchal males disappeared. My organization has a subscription to the source material, i'll try to read it and maybe clarify once I'm done. BRB. :P

I read the article and they are not arguing against the notion that males naturally have more spatial reasoning ability than females. They do not dispute that males have stronger spatial reasoning abilities than females. Their main claim is that it's not 100% nature, and that there is *some* nurture component to it. Their data shows this.

They wrote the article in the context of looking into the reason why women aren't more represented in science and engineering fields. They argue that with education and encouragement, women can develop strong spatial reasoning skills and increase their representation in the science and engineering fields. That's all they really say.

This article reminded me of the case I know of where a female scored 800 on both her verbal and math scholastic aptitude test. I actually know her brother much better. He is a very competitive and academically ambitious person who succeeded in making a very successful career in science and has become a member of the National Academy of Science. But he could not manage to be in the top group in the math or physics courses that we took together in college. His sister did not succeed in making a career on the same scale. Nor did I for that matter even though I did do significantly better in math and physics. I have little doubt that genes played a significant part in all of these outcomes. The female's problem was that she had to cope with mental disease that almost certainly had a genetic component. Her brother's inability to do as well at math as he would have liked is hard to explain any other way than by some genetic component. His capabilities that made him good at careers certainly had something to do with a parental role model and likely also with his high school experience in a very competitive environment. But different people who experience the same environment don't have the same outcomes. Real scientific studies with identical twins provide real scientific evidence that genes are responsible for a large component of these differences Whatever biases there are about sex and mathematics in our society, they are weak. The grade school and high school I attended had both male and female students who received exactly the same training in exactly the same classes. Nobody told the females they could not do mathematics. It is hard to believe that this kind of environment would hold back a woman with exceptional skill in mathematics who was born to be another Einstein.

In the patrilinial society, men outperformed women on this task, taking 35 percent less time to complete it than the females. That difference vanishes when the test is given to the matrilinial tribe members; there was simply no significant difference between the sexes.

So we have the 35% gap between men and women in the patrilinial society.We have that gap disappear when measuring women in the matrilinial society.

That can be read as either women and men performing equally in the matrilinial society, or that women outperformed men in the matrilinial society but equal to the men in the patrilinial society. The issue is the term "that", which doesn't indicate which to populations was being measured.

Yeah, the sentence structure here is really confusing at a critical point in the article. My problem with it is that a comparison is made between the two situations when they are in fact separate studies. We don't know anything from the description given about how women in the matrilineal society compare to men in the patrilienal society: we only have evidence of they compare to their respective counterparts in their own cultures. Saying a gap in one disappears in the other is an arbitrary statement. One has a gap, the other doesn't. It's not that the gap is fundamental and then disappears. Bad bad wording.

@Inkling: I think you're over analyzing the college ads. Isn't it just an example of typical marketing strategies? Women see lots of women in the ads and feel solidarity. Men see lots of women in the ads and get horny. Or are there a ton of heterosexual guys out there that want to go to college with mostly men? It wouldn't surprise me a bit if I were to find that women dominate ads as a whole, period.

I agree with those saying this study might actually support a biological difference in spatial reasoning between the sexes. In the male-dominated society, males did better on the test. In the female-dominated society, females did NOT do better than the males. They simply pulled even.

It also may show a societal influence as well. Both may be factors.

Who said the matrilineal society is "female dominated"? Just because women have certain privileges, does not by any means imply its a female dominated society.